1. Field of the Invention
This invention relates generally to networks that require Quality-of-Service (QoS) parameters for data traffic streams, including streaming audio and/or video (audio-video or “AV”), and more particularly to a system and method for managing QoS resources, such as available network bandwidth.
2. Description of the Related Art
Quality-of-Service (QoS) in the field of packet-switched networks refers to a broad collection of networking capabilities and techniques to assure that a packet succeeds in passing between two points in the network. QoS elements of network performance typically include bandwidth (throughput), latency (delay), and error rate. The goal of QoS is to improve the user experience of a network's ability to deliver predictable results for sensitive applications. Certain types of network traffic streams, such as streaming AV, may require QoS to guarantee throughput. These types of traffic require a certain level of bandwidth to function—any more than required is unused, and any less will render the service non-functioning.
QoS is becoming increasingly important in local area networks (LANs) used in the home. These home LANs may use a wide variety of existing cabling or non-engineered placement of wireless access points with technologies that have varying underlying bandwidth. Home LANs tend to use applications that are AV-intensive with different bandwidth characteristics and typically include consumer electronic (CE) devices like stereo receivers, digital video recorders (DVRs), digital TVs and AV servers. Home LANs typically include wired LANs, like 10/100baseT Ethernet, and wireless local area networks (WLANs), such as those based on the well-known IEEE 802.11 or Wi-Fi standards. Other types of WLANs include ultrawideband (UWB) networks that have a fairly short range but very high throughput. Another type of LAN, one that does not use wireless transmission, is a powerline communications (PLC) network that uses the existing electrical wiring in a home or single building, such as a PLC network based on the HomePlug™ standard.
In any network with managed QoS, including home LANs with AV applications, there are scenarios in which multiple requesters compete for QoS resources such as bandwidth. In the case where all requested traffic streams have equal priority the bandwidth is allocated on a first-come-first-serve basis. However, in the case where a high-priority request is made after the needed bandwidth is already allocated to lower-priority requestors, existing allocations must be pre-empted to accommodate the new high priority request. The need to pre-empt lower-priority allocations raises issues such as which existing allocations are pre-empted, can they be at least totally or partially reallocated, and how original requestors of pre-empted allocations should be notified. It is important to have a robust and efficient method to address these issues or diminished user experience and excessive messaging may occur in the network. Additionally, problems such as race conditions and QoS violations may arise.
What is needed is a system and method for managing pre-emption and reallocation of QoS allocations in a network in an efficient and non-disruptive manner.